Wavelength-division-multiplexing method of polarized low-coherence interferometry for fiber Fabry–Perot interferometric sensors

2013 ◽  
Vol 38 (19) ◽  
pp. 3751 ◽  
Author(s):  
Jinde Yin ◽  
Tiegen Liu ◽  
Junfeng Jiang ◽  
Kun Liu ◽  
Shuang Wang ◽  
...  
Keyword(s):  
Wavelength Division Multiplexing ◽  
Wavelength Division ◽  
Low Coherence ◽  
Interferometric Sensors ◽  
Low Coherence Interferometry ◽  
Fabry Perot

scholarly journals Thermo-Optic Tunable Optical Filter Based on Fabry-Perot Microcavities in SOI

2012 ◽  
Vol 6-7 ◽  
pp. 194-199
Author(s):  
Zhe Li ◽  
Hua Juan Qi ◽  
Yong Chuan Xiao ◽  
Feng Li Gao
Keyword(s):  
Refractive Index ◽  
Wavelength Division Multiplexing ◽  
Optical Filter ◽  
Silicon On Insulator ◽  
Central Wavelength ◽  
Wavelength Division ◽  
Tunable Optical Filter ◽  
Compact Size ◽  
Fabry Perot ◽  
Output Characteristics

An integrated TOF (Tunable Optical Filter) based on thermo-optic effect in Silicon on insulator (SOI) rib waveguide is designed and simulated. The device is comprised of two high refractivity contrast Si/Air stacks, functioning as high reflectivity of DBRs and separated by a variable refractive index Si F-P cavity. The output characteristics are calculated and simulated based on Transfer Matrix Method (TMM). Wavelength tuning is achieved through thermal modulation of refractive variation of the cavity.As the cavity Si is heated,the refractive index of the cavity increases.When the temperature of cavity Si changes within100°C，the central wavelength gets a continuous 8nm shift from 1550nm to 1558nm, which is right located in the WDM (Wavelength division multiplexing) networks operating at C-band. Moreover, by calculating, the tuning sensitivity is about 0.08nm/°C. Owing to the compact size and excellent characteristics of integration, the proposed component has a promising utilization in spectroscopy and optical communication.

scholarly journals Demodulation Method of F-P Sensor Based on Wavelet Transform and Polarization Low Coherence Interferometry

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4249
Author(s):  
Jiwen Cui ◽  
Yizhao Niu ◽  
Hong Dang ◽  
Kunpeng Feng ◽  
Xun Sun ◽  
...  
Keyword(s):  
Cavity Length ◽  
Sampling Interval ◽  
Low Coherence ◽  
Low Coherence Interferometry ◽  
Data Processing Method ◽  
Fabry Perot ◽  
Complex Morlet Wavelet ◽  
Influence Of Noise ◽  
Demodulation Method ◽  
Better Than

Polarized low-coherence interferometry (PLCI) is widely used for the demodulation of Fabry–Perot (F-P) sensors. To avoid the influence of noise and dispersion on interference fringes, this paper proposes a data processing method in which the wavelet tools are applied to extract useful information from the extremum locations and envelope center of the fringes. Firstly, the wavelet threshold denoising (WTD) algorithm is used to remove electrical noise, and the complex Morlet wavelet is used to extract the fringe envelope. Based on this, the envelope center is used to predict the extremum locations of the specified order in its adjacent interval, the predicted locations are used as references to track the exact extremum locations, and the middle location of the peak and valley values is obtained to demodulate the F-P cavity accurately. The validity of this demodulation theory is verified by an air F-P cavity whose cavity length varies from 17 to 20 μm. With a sampling interval of 30 nm, the experimental results indicate that the repeatability accuracy is higher than 6.04 nm, and the resolution is better than 4.0 nm.

scholarly journals From Light to Displacement: A Design Framework for Optimising Spectral-Domain Low-Coherence Interferometric Sensors for In Situ Measurement

2020 ◽  
Vol 10 (23) ◽  
pp. 8590
Author(s):  
Tom Hovell ◽  
Jon Petzing ◽  
Laura Justham ◽  
Peter Kinnell
Keyword(s):  
Spectral Domain ◽  
Design Framework ◽  
Object Surface ◽  
Low Coherence ◽  
Interferometric Sensors ◽  
Spectral Domain Oct ◽  
Low Coherence Interferometry ◽  
Definition Of ◽  
In Situ Metrology

Growing requirements for in situ metrology during manufacturing have led to an increased interest in optical coherence tomography (OCT) configurations of low coherence interferometry (LCI) for industrial domains. This paper investigates the optimisation of spectral domain OCT hardware and signal processing for such implementations. A collation of the underlying theory of OCT configured LCI systems from disparate sources linking the journey of the light reflected from the object surface to the definition of the measurand is presented. This is portrayed in an applicable, comprehensible design framework through its application to profilometry measurements for optimising system performance.

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